Lens.



No. 766,036. PA'TENTED JULY 2611904.

H. HARTING.

LENS.

APPLICATION mum FEB. 17, 1904.

no MODEL.

UNITED STATES Patented July so, 1904,

PATENT OFFICE.

HANS HARTING, or BRUNSWICK, GERMANY.

LENS.

' SII'ECIFIGATIONI forming part of Letters Patent No. 766,036, dated Ju1y 26,1904.'

Application filed February 17, 1904. Serial No. 193,936. on model.)

To all whom it may concern:

Be it known'that I, HANS HARTING, director, a sub ect of the Emperorof Germany, residing at Brunswick, Duchy of Brunswick, Em-

pire of Germany, have invented certain new and useful Improvements in Lenses, of which the following is a specification.

Chromatically, spherically, and astigmatically corrected lens systems are known in which a third-lens system, which is symmetrical in itself and symmetrical to the outer systems,

is placed between two symmetrical lens systerns composed of at least two lenses, (crown and fiint,) which lens systems both simultaneously containcrown-glass of higher or crownglass of lower refraction than the flint-glass,

the lenses of which third-lens system" (which lenses, face the two outer lens systems) each form a glass pair with the lenses which face them of the outer systems, in which glass pair the glass with the smaller color dispersion has an index of refraction larger than or tern.

' system A the diverging approximately equal to that'of the other.

Now this invention .has for'its object such a modification of such a lens system asallows in addition to a good correction of optical defects alsoa good correction of the remaining aberration to be effected and also a sharp,

brilliant, and level picture over a wide field of vision with a relatively wide objective. This is attained by the converging and diverging lenses in the two outer systems having different positions with respect to the middle systemthat is to say, the converging and diverging lenses of the outer systems being consist of one single lens or of several lenses.

' Both of the outer systems A and B must con- -sist at the least of two lenses, of which one must be crown-glass and the other flint-glass.

tems in addition. If in system A the crownglass lens has a higher refraction than the flint-glass lens, then in system B the crownglass lensmust also have a higher refraction than the flint-glass lens; but if in system A the crown-glass lens has a lower refraction than the'flint-glass lens then in said system B the crown-glass lens must havea lower refraction than the flint-glass. lens; If in said system A the diverging lens is placed on the be placed on the inside and the converging lens on the outside; This improved construction has also the advantage that there is' "greater choice of available kinds of glass than the older type of lens hereinbefore mentioned allows.

a A form of construction shown in the accompanying drawing will now be explained as an example the lenses be-assumed to-be indicated as shown in the drawing by r1 1'; 1'3 1'4 1'5 7'0 2'1 7'8 and the lens thicknesses or air-s ce measured on the optical-axis by (11 d2 3 d; da da Jr, the following equivalents re'sult,,for instance, for an Diameter of aperture, 222i relative aperture, 1:4;5, (f/4.5.)

, The stop eis 51 There can also be other lenses in these systuated in the second air-space.

outside and the converging lens on the inside, then in said system B the diverging lens must If the eight different radii of curvature of V I Y The equivalents of the kinds'of glassfindices' ofi'efraction'for the frauenhofer lines Dand G Hy) are then the following:

' glass.)

Formmn 1.61340, M l.l i2736,(heaviest baryta crown.)

I5 I declare thatwhat-I claim is- A lens system, consisting of a central sys- For 62m.) 1.53780, m": 1.55143, (silicate tem and two outer systems each of theouter systems having-a converging and diverging lens, one of said lenses being of crown-glass and the other of flint-glaSs-the-refractionof which is different in the same sense .in both outer systems, said converging, and diverg ing lenses of the outer systems being arranged unsymmetrically to the central system.

. In testimony whereof I have hereunto set 5 my hand in presence of two snbscr'ibingwitnesses.

HANS HARTIlSIG.

Witnesses: I r

- JULrUs SEOKEL,

WILHELM Ln nmn, 

